Mechanical Behavior of Carbon Fiber Composites Produced with Fused Filament Fabrication

Fused Filament Fabrication (FFF) is a commonly used Additive Manufacturing (AM) technique. However, the printed parts often lack sufficient mechanical integrity. Recently, mechanical properties of FFF filament have been enhanced by blending pure polymer with short carbon fibers. This paper presents a study of the mechanical properties for carbon fiber filled (CFF) FFF parts produced with Makerbot printers. Polymer composite and pure polymer tensile test coupons are printed and then tested following ASTM D3039M. Here we consider FFF print orientations that are aligned with the test bar axis at 0 degree, 45 degrees, ±45 degrees, and normal to the bar axis at 90 degrees. The filament considered here was purchased from filament suppliers and included PLA, ABS, and PETG. Results are presented for tensile strength and tensile modulus. Additionally, short fiber composite samples are evaluated for fiber length distribution (FLD) and fiber weight fraction. Fracture surfaces are evaluated under SEM.